1. Field
Embodiments disclosed herein relate to an image forming apparatus having a structure which prevents contamination of charging units charging photoconductors forming images.
2. Description of the Related Art
Image forming apparatuses form an image on a printing medium according to an input signal, may include a printer, a copying machine, a scanner, a facsimile and a multi-function apparatus combining functions of two or more of a printer, a copying machine, a scanner or a facsimile.
An electrophotographic image forming apparatus which is a kind of image forming apparatus includes a developing device including photoconductors, charging units and developing units, and a light scanning unit. The light scanning unit irradiates light to the photoconductors charged with designated potential by the charging units to form electrostatic latent images on the surfaces of the photoconductors, and developing units supply developers to the photoconductors on which the electrostatic latent images are formed to form visible images.
There are various charging methods to charge photoconductors. Among the various charging methods, one method includes charging the surfaces of photoconductors using corona discharge, in which a charge potential of the photoconductors may be stabilized by controlling charge current by grid bias applied to a grid. However, various discharge oxides, such as ozone and nitrogen oxides, may be generated by the discharge according to a strong charge current. Therefore, a separate device to remove the discharge oxides harmful to human health is required. Dust having fine particles and toner around the charging units and the photoconductors may be sucked together with the discharge oxides during a process of sucking air including the discharge oxides to remove the discharge oxides. This may result in contaminating the charging units, and cause degradation of image quality.